JP2019510122A - Manufacture of matte paint and printing ink - Google Patents

Abstract

  The present invention relates to pigment compositions for producing matte coatings colored with pigments such as matte paints and printing inks. Furthermore, the present invention relates to a method for producing such a pigment composition and a coating formulation containing such a composition. Finally, the present invention relates to a matte surface colored with the pigment of the substrate and the use of the pigment composition disclosed herein for matting the substrate.

Description

TECHNICAL FIELD The present invention relates to a pigment composition for producing matte coatings colored with pigments such as matte paints and printing inks. Furthermore, the present invention relates to a method for producing such a pigment composition and a coating formulation containing such a composition. Finally, the present invention relates to a matte surface colored with the pigment of the substrate and the use of the pigment composition disclosed herein for matting the substrate.

TECHNICAL BACKGROUND OF THE INVENTION Surface matting is performed by selectively roughening the surface in the micro range. Thus, the impinging light is no longer directionally reflected but diffusely reflected. The glossiness of the coating film or printing ink is determined by the height, shape and number of surface structures.

  Usually, a matte surface is obtained by adding a specific matting agent to a paint or printing ink composition. Typical matting agents are spherical particles having a particle size in the range of 1 to about 20 μm depending on the film layer thickness. In practice, precipitated or pyrogenic silicas or silica gels are mainly used as matting agents, but matting agents based on thermosetting resins, waxes or thermoplastic resins are also used. Furthermore, the compatibility of silicates, calcium carbonate, and various types of hollow spheres is also known.

Thus, EP 1398301 (EP 1 398 301 B1) is based on precipitated silica having a particle size (d50) in the range of 5-15 μm and a specific surface area (BET) of 350-550 m ² / g. Matting agents for paints and lacquers are disclosed. Silica is optionally coated with wax.

  German Offenlegungsschrift 19 156 253 (DE 195 16 253 A1) discloses matting agents based on spray-dried silica gel. In order to ensure sufficient stability of the agglomerates, binders such as layered silicates, pyrogenic silica or organic polymers are used. This matting agent has a particle size of 1-20 μm and a specific pore volume of 0.4-2.5 ml / g.

  In general, the matting effect increases with the amount of matting agent used. The larger the particles, the higher the matting effect, but it is not desirable because a smooth surface cannot be obtained. Furthermore, as the content of matting agent increases and the dispersion time increases, the viscosity of the coating system increases, thus causing processing problems. Also, known matting agents based on silica are difficult to handle due to their strong dusting tendency and are therefore disadvantageous.

  According to the patent application EP 1 530 003 (EP 1 500 3103), these drawbacks are due to the use of pigment masses having an average particle size d50 of 2 to 200 μm in the production of matte paints and printing inks. Avoided. This method is characterized in that the pigment mass is partially disintegrated during dispersion, for example in a bead mill, but no increase in viscosity occurs. A further feature of this method is that the matting agent and the pigment have the same chemical composition and surface properties. The disadvantage of this method is that the degree of matting is highly dependent on the input of dispersion energy because the pigment mass is partially collapsed.

  Accordingly, there is a need in the art for a matting agent to produce a matte coating that is less dusty, dispersion stable, and that allows for a more reproducible surface with a uniform matte appearance. Further, there is a need for a method for producing a matte coating colored with a pigment in which the matting agent has a composition similar to that of a pigment, but the matting effect is not affected by the dispersion method.

The problems underlying the invention and the brief description The technical problem underlying the present invention is a pigment composition for producing a pigmented matte coating, a process for producing such a composition, and a coating formulation comprising such a pigment composition. As well as the use of said composition for matting substrates.

  The subject is a pigment composition for producing a matte coating, the pigment composition comprising inorganic pigment particles having a mass-based bimodal particle size distribution, wherein the first particle fraction has a colorability The second particle fraction has an average particle size (d50) in the range of 2 to 200 μm, preferably 2 to 100 μm, more preferably 2 to 50 μm, most preferably 2 to 20 μm. The first and second particle fractions are solved by the pigment composition, characterized in that they are surface treated.

  The pigment composition according to the invention has good mattness and excellent opacity. The composition also has high impact and wear resistance and improved chemical stability. With the introduction of this composition, the particles do not disintegrate, so the matting effect and the viscosity of the coating formulation do not change significantly, the formulation is easily prepared and easy to handle and apply. Furthermore, because of the similar viscosity and matrix behavior that allow the compositions according to the invention to be used, only a slight compatibility is required for formulations composed of gloss paints.

  Accordingly, in a first aspect, the present invention provides a pigment composition for producing a matte coating, the pigment composition comprising inorganic pigment particles having a mass-based bimodal particle size distribution, The particle fraction has a colorable particle size and the second particle fraction is an average within the range of 2 to 200 μm, preferably 2 to 100 μm, more preferably 2 to 50 μm, and most preferably 2 to 20 μm. The pigment composition has a particle size (d50), and the first and second particle fractions are surface-treated.

In a further aspect, the present invention is a method of making a pigment composition for matte coating comprising the steps of:
(A) preparing a first inorganic pigment particle fraction having a colorable particle size;
(B) preparing a second inorganic pigment particle fraction having an average particle diameter (d50) in the range of 2 to 200 μm, preferably 2 to 100 μm, more preferably 2 to 50 μm, and most preferably 2 to 20 μm. And (c) the first and second pigment particle fractions are subjected to a surface treatment in an aqueous suspension.

  In another aspect, the invention relates to a coating formulation comprising a pigment composition according to the invention.

  In yet another aspect, the present invention is a matte surface colored with a pigment of a substrate, characterized in that the surface is coated with a coating formulation according to the invention. Related to matte surface.

  In another aspect, the invention relates to a matte coating colored with pigments such as paints and printing inks, characterized in that it uses a pigment composition according to the invention. .

  In a further aspect, the invention relates to a plastic comprising a matting agent, characterized in that the plastic comprises a pigment composition according to the invention.

  Finally, in another aspect, the present invention relates to the use of a pigment composition for matting a substrate.

  Further advantageous embodiments of the invention are described in the dependent claims.

DETAILED DESCRIPTION OF THE INVENTION These and further aspects, features, and advantages of the present invention will become apparent to those skilled in the art from the following detailed description and a study of the claims. Each feature from one aspect of the invention can be used in any other aspect of the invention. Further, it is to be understood that the examples included herein are merely intended to illustrate and illustrate the present invention, but are not intended to limit the invention, and in particular, the invention is not limited to such examples. It is not limited to. Numerical ranges stated in the format “x to y” include the stated values and values within the respective measurement accuracy ranges, as known to those skilled in the art. Where some preferred numerical ranges are described in this format, of course, all ranges made by combining various endpoints are also included.

  The percentages defined for the compositions described herein relate to weight percentages, respectively, based on the mixture or composition according to the invention, unless otherwise specified.

  As used herein, “at least one” means one or more, ie 1, 2, 3, 4, 5, 6, 7, 8, 9 or more. For a component, the value relates to the type of component, not the absolute number of molecules. This value, in combination with the description of the mass, relates to all compounds of the type described which are included in the composition / formulation, which means that the composition / formulation will add further compounds of this type to the corresponding compounds. It means that it does not contain exceeding the stated amount.

  Within the scope of the present invention, “average particle diameter” means the mass-based median d50, hereinafter referred to as d50. The particle size distribution and mass-based median d50 were measured by the sedimentation method described herein.

  As used herein, “pigments” are inorganic or organic colorants that are virtually insoluble in the application medium according to DIN 55943 and do not change chemically or physically in the application medium and retain their particle structure. It relates to the agent. They are used for coloring based on the interaction of absorption and reflection between pigment particles and visible light. The “colorable particle diameter” used in the present specification is an average particle in the range of 0.01 to 1 μm, preferably 0.2 to 0.5 μm, more preferably 0.2 to 0.4 μm. It refers to the diameter (d50).

  Inorganic pigments known in the art and suitable for the purposes according to the invention can be used as said inorganic pigment particles. Preferably, the inorganic pigment particle is a metal salt, and more preferably, the metal salt is a metal oxide.

  Suitable inorganic pigments include white pigments such as titanium dioxide (CI Pigment White 6), zinc white, lead zinc oxide; zinc sulfide, lithopone; black pigments such as iron oxide black (CI pigment). Black 11), iron manganese black, spinel black (CI pigment black 27); carbon black (CI pigment black 7); color pigments such as chromium oxide, chromium oxide hydrate green; CI Pigment Green 48); Cobalt Green (C.I. Pigment Green 50); Ultramarine Green; Cobalt Blue (C.I. Pigment Blue 28 and 36; C.I. Pigment Blue 72); Manganese blue; ultramarine violet; cobalt and Manganese violet; iron oxide red (CI pigment red 101); cadmium sulfoselenide (CI pigment red 108); cerium sulfide (CI pigment red 265); molybdenum red (CI pigment) Red 104); Ultramarine Red; Iron Oxide Brown (CI Pigment Brown 6 and 7), Mixed Brown, Spinel and Corundum Phases (CI Pigment Brown, 29, 31, 33, 34, 35, 37, 39 and 40), chrome titanium yellow (CI Pigment Brown 24), chrome orange; cerium sulfide (CI Pigment Orange 75); iron oxide yellow (CI Pigment Yellow 42); nickel titanium yellow ( CI Pigment Yellow 53; Pigment Yellow 157, 158, 159, 160, 161, 162, 163, 164 and 189); Chromium Titanium Yellow; Spinel Phase (CI Pigment Yellow 119); Yellow 37 and 35); chrome yellow (CI Pigment Yellow 34), and bismuth vanadate (CI Pigment Yellow 184).

  Inorganic pigment particles conventionally used as fillers such as aluminum oxide, aluminum hydroxide, zinc sulfide, natural and precipitated chalk and barium sulfate can also be used.

  Preferably, the pigment particles are selected from the group consisting of magnesium carbonate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, huntite, lead white, lithopone, cristobalite, china clay and mixtures thereof. Of all the pigment particles disclosed herein, titanium dioxide is most preferred due to its pigment properties and its high Mohs hardness. Titanium dioxide exists in a rutile, anatase or brookite crystal structure and can usually exist in a rutile or anatase crystal structure. The rutile type is particularly suitable compared to the anatase type because of its low photolytic catalytic activity.

  When titanium dioxide is used, untreated titanium dioxide particles (titanium dioxide-based pigments) produced by the sulfate method or chloride method are usually used as starting material for the first particle fraction according to the invention. The The colored titanium dioxide-based pigment usually has an average particle diameter d50 of 0.2 to 0.5 μm, preferably 0.2 to 0.5 μm, more preferably 0.2 to 0.4 μm. A non-coloring coarse titanium dioxide pigment having an average particle diameter d50 of 2 to 200 μm, preferably 2 to 100 μm, more preferably 2 to 50 μm, most preferably 2 to 20 μm is used as the second particle fraction. Is done. For example, the rough titanium dioxide pigment may be a rutile type produced by a sulfate method or a chloride method. These particles may have a particle size d50 of up to about 2 mm, optionally pulverized to the desired particle size range, and optionally classified, for example by screening. The grinding can be performed, for example, in a stirring bead mill, a pendulum mill, or a roller mill. In the production of titanium dioxide by the sulfate method, the desired particle size is obtained during the addition of certain additives, longer firing times and / or firing at higher firing temperatures. The produced particles are characterized by stronger sintering, and therefore they are very stable within the coating coverage during subsequent dispersion, i.e. they do not collapse. In certain embodiments, titanium dioxide particles obtained from a chloride process that has undergone a sintering process may be used.

  Preferably, the pigment particles of the coating material are surface treated with a compound of aluminum, silicon, titanium, zirconium, tin, cerium or phosphorus and / or an organic compound selected from the group of silane, siloxane, TMP, TME and HMP. ing.

  Furthermore, in a preferred embodiment of the present invention, the first and second particle fractions are subjected to the same surface treatment. In this way, both particle fractions have substantially the same surface properties, in particular matrix compatibility with surface active additives, so that their ease of handling is greatly improved.

  Preferably, the second particle fraction is present in the pigment composition in an amount of 1 to 10% by weight, preferably 1 to 6% by weight, based on the total weight of the pigment composition.

The process according to the invention for producing a pigment composition for matte paints comprises:
(A) preparing a first inorganic pigment particle fraction having a colorable particle size;
(B) preparing a second inorganic pigment particle fraction having an average particle diameter (d50) in the range of 2 to 200 μm, preferably 2 to 100 μm, more preferably 2 to 50 μm, and most preferably 2 to 20 μm. And (c) surface treating the first and second pigment particle fractions in an aqueous suspension.

  In the production of titanium dioxide by the sulfate method, the desired particle size is obtained during the calcination with the addition of certain additives and with a longer calcination time and / or higher calcination temperature. The produced particles are characterized by a stronger sintering and therefore they are very stable within the coating coverage during the subsequent dispersion, i.e. they do not collapse. In certain embodiments, titanium dioxide particles obtained from a chloride process that has undergone a sintering process may be used.

  Thereafter, the pigment particles are subjected to a surface treatment with an inorganic compound and / or an organic compound. The surface treatment usually corresponds to a surface coating applied to the pigment. Coating materials include, for example, Si, Al, Ti, Zr, Sn, Ce or P compounds, or organic compounds such as silane, siloxane, trimethylolpropane (TMP), trimethylolethane (TME), hexametaphosphate ( HMP) and the like. Thus, the matting agent has surface characteristics similar to those of commonly used pigments, for example with respect to matrix compatibility, especially with respect to surface active additives.

  For surface treatment, one or more layers or mixed layers of coating materials may be applied. In a particular embodiment of the invention, the outer layer of surface treated particles comprises an Al compound, in particular aluminum oxide or hydrous aluminum oxide. The surface treatment is performed, for example, by precipitating the coating material on particles in an aqueous suspension. These methods are known in particular from titanium dioxide pigment technology and can be applied according to the invention. The layer thickness of the surface coating applied to the particles within the surface treatment is in the nanometer range, preferably less than 10 nm, more preferably 1 nm to 10 nm, and the particle size of the surface treated particles is not yet There is no significant change compared to the treated particles.

  The surface treatment of both particle fractions is preferably carried out in the same way by treating both particle fractions together with the same suspension or treating each particle fraction separately with the suspension. Is called. In the first case, a suspension containing both particle fractions is prepared having a proportion of the second particle fraction of 1 to 10% by weight, preferably 1 to 6% by weight, based on the weight of the total particles. The Subsequently, in this suspension, the particles are surface treated, separated, washed, dried as usual and micronized as usual. In the second case, each particle fraction is surface treated separately in suspension, then separated, washed, dried, micronized and finally mixed in the dry state in the desired quantity ratio. The

  Following surface treatment, the particles are separated, filtered, washed, dried, and optionally micronized, for example, with a steam jet mill. Micronization is usually performed in a steam jet mill, and an organic compound such as TMP or TME may be added during that time. Those skilled in the art know such methods.

  The present invention further relates to a coating formulation for producing a pigmented matte surface containing the pigment composition described herein. The composition is coated in an amount of 0.1 to 98%, preferably 1 to 50%, more preferably 2 to 25%, most preferably 3 to 23% by weight, based on the total weight of the coating formulation. It can be included in the formulation. In addition to the pigment composition according to the present invention, the formulation may include conventional pigment compositions and pigments. Preferably, the formulation contains no further pigment composition.

  In addition, the formulation contains the usual ingredients. Any of the components known in the prior art suitable for the purposes according to the invention can be used as components. Preferably, the formulation comprises at least one component selected from the group consisting of binders, antifoams, dispersants, fillers, solvents, preservatives, auxiliary film formers, and rheological additives. The preservative includes a normal disinfectant. Coating formulations include lacquers, paints, and printing inks.

  The present invention further relates to a matte surface colored with a base pigment, characterized in that said surface is coated with a coating formulation as disclosed herein. Formulations can be in the form of one-part, two-part, and multi-component paints established in conventional compositions. The paint is applied to the substrate by conventional techniques and methods and is cured, for example by UV irradiation or drying, depending on the paint composition, particularly the binder. Substrates include, but are not limited to wood, plastic, metal, paper, glass fiber, and mixtures thereof.

  In the finished coating, the first colorable pigment particle fraction (first particle fraction) provides coloration and a second coarser pigment particle fraction (d50 in the range of 2 to 200 μm) is sought. Provides surface roughness.

  The present invention further relates to a plastic characterized in that said plastic comprises the pigment composition of the present invention. Any plastic known in the prior art and suitable for the purposes according to the invention can be used as plastic. “Plastic” as used herein relates to a material comprising at least 50% polymer by weight, based on the total weight of the plastic. The polymer can be a homopolymer, a copolymer, or a graft polymer. The polymer can also be an atactic, isotactic or syndiotactic polymer. Furthermore, the plastic is a thermoplastic resin, an elastomer, a duroplast or a thermoplastic elastomer, preferably a thermoplastic resin. The polymer is selected from, but not limited to, the group consisting of polyolefin, polystyrene, polyamide, polyketone, polyester, polyurethane, poly (meth) acrylate, and mixtures thereof. The polyolefin is selected from the group consisting of, but not limited to, polymethylene, polyethylene, polypropylene, polybutylene, and mixtures thereof. The composition according to the invention can be incorporated into plastics by known techniques and methods, for example extrusion. The compositions described herein are particularly advantageous in extrusion processes because they do not disintegrate therein and extrusion does not affect the matte effect. Matting agents are processed into plastics in normal amounts. Accordingly, the plastic obtained contains 0.1 to 30% by weight, preferably 1 to 25% by weight of the matting agent according to the invention, based on the total weight of the plastic.

  Finally, the invention further relates to the use of a pigment composition for matting a substrate. As noted above, substrates include, but are not limited to, wood, plastic, metal, paper, glass fiber, and mixtures thereof.

Test method Particle size distribution and mass-based median d50
In this method, the concentration shift of the aqueous suspension of particles that settles under the influence of gravity is used to calculate its particle size distribution. The change in density was detected by X-ray. The loss of intensity due to absorption at the particles represents the degree of solids concentration in the beam path. The particle diameter is calculated from the fixed sedimentation velocity of the particles based on Stokes' law.

Flow viscosity The flow viscosity was measured using the DIN 5321 method. The finished paint is poured into a defined-shaped flow cup with a 4 mm diameter outlet capillary. When the outlet is opened, the liquid flows under its own weight to the central outlet at the bottom of the cup. When the flow time is measured by optical scanning of the outgoing fluid flow using a Cuptimer 243 T automatic flow time measurement station, the measured time is immediately displayed on the unit.

Contrast ratio The contrast ratio was measured by standard techniques using equipment such as a color guide sphere from Byk gardner and a foil Hostaphan RNK 23 available from Jakob Benn & Soehne.

Example 1a
Coarse fine particles, non-colorable titanium dioxide were fired until firing. The fired material (220 g) was pulverized, and the particle size was classified by the precipitation method Atterberg precipitation method. The obtained aggregate had a particle diameter d50 m of 17 (+/− 2) μm. This fraction was post-treated with an alumina layer. When the amount of alumina was calculated, the layer thickness was the same as that of the white pigment used.

Example 1b
Example 1b includes the preparation of Example 1a except that no post-treatment was performed.

Example 2
The standard formulation is based on nitrocellulose supplied in the form of chips dissolved in ethanol and ethyl acetate. Other components are plasticizers and further additives for improving surface and gloss. After the vehicle is prepared and weighed into the pigment composition, the blend is dispersed in a Skandex disperser using ground beads.

Comparative Example 1
Comparative Example 1 includes the preparation of the standard formulation described in Example 2, wherein the pigment composition is marketed under the product name Kronos 2066 from Kronos International Inc., post-treated with alumina. It is a rutile type crystal modified titanium dioxide pigment. Flow viscosity and gloss (20 °, 60 °, 85 °) were measured as described above. Data can be seen from Table 1.

Comparative Example 2
Comparative Example 2 comprises the preparation of a standard formulation as described in Example 2, wherein the pigment composition is a rutile crystal modification dioxide marketed under the product name Kronos 2066 from Kronos International, post-treated with alumina. Titanium pigment (97% by mass based on the total amount of the composition) and a commercially available matting agent Acematt TS100 (3% by mass based on the total amount of the composition). Flow viscosity and gloss (20 °, 60 °, 85 °) were measured as described above. Data can be seen from Table 1.

Comparative Example 3
Comparative Example 5 comprises the preparation of a standard formulation as described in Example 2, wherein the pigment composition is a rutile crystal modification dioxide marketed under the product name Kronos 2066 from Kronos International after-treatment with alumina. Titanium pigment (94% by mass based on the total amount of the composition) and a commercial matting agent Acematt TS100 (6% by mass based on the total amount of the composition). Flow viscosity and gloss (20 °, 60 °, 85 °) were measured as described above. Data can be seen from Table 1.

Example 3
Example 3 comprises the preparation of a standard formulation as described in Example 2, wherein the pigment composition is a rutile crystal modification dioxide sold under the product name Kronos 2066 from Kronos International post-treated with alumina. Titanium pigment (97% by weight based on the total amount of the composition) and the material of Example 1b (3% by weight based on the total amount of the composition). Flow viscosity and gloss (20 °, 60 °, 85 °) were measured as described above. Data can be seen from Table 1.

Example 4
Example 4 comprises the preparation of a standard formulation as described in Example 2, wherein the pigment composition is a rutile crystal modification dioxide marketed under the product name Kronos 2066 from Kronos International, post-treated with alumina. Titanium pigment (94% by mass based on the total amount of the composition) and the material of Example 1b (6% by mass based on the total amount of the composition) are included. Flow viscosity and gloss (20 °, 60 °, 85 °) were measured as described above. Data can be seen from Table 1.

Example 5
Example 5 includes the preparation of a standard formulation as described in Example 2, wherein the pigment composition is a rutile crystal modification dioxide marketed under the product name Kronos 2066 from Kronos International, post-treated with alumina. Titanium pigment (97% by weight based on the total amount of the composition) and the material of Example 1a (3% by weight based on the total amount of the composition). Flow viscosity and gloss (20 °, 60 °, 85 °) were measured as described above. Data can be seen from Table 1.

Example 6
Example 6 comprises the preparation of a standard formulation as described in Example 2, wherein the pigment composition is a rutile crystal modification dioxide marketed under the product name Kronos 2066 from Kronos International post-treated with alumina. Titanium pigment (94% by weight based on the total amount of the composition) and the material of Example 1a (6% by weight based on the total amount of the composition) are included. Flow viscosity and gloss (20 °, 60 °, 85 °) were measured as described above. Data can be seen from Table 1.

  Compared with a comparative paint produced using a commercially available titanium dioxide pigment, and further compared with a comparative paint produced using a commercially available matting agent (Comparative Examples 2 and 3), a paint produced according to the present invention (Example 3) 4, 5, 6) have a lower viscosity. The matte paints produced in accordance with the present invention (Examples 3, 4, 5, 6) have a marked viscosity compared to the gloss paint produced using commercially available titanium dioxide containing no matting agent (Comparative Example 1). It shows a good matting effect without showing an increase. Furthermore, paints according to the invention containing particles with similar post-treatment (Examples 5 and 6) are compared with paints according to the invention with particles without similar post-treatment (Examples 3 and 4). Improved viscosity characteristics.

Claims (15)

A pigment composition for producing a matte coating,
The pigment composition comprises inorganic pigment particles having a mass-based bimodal particle size distribution,
The first particle fraction has a colorable particle size;
The second particle fraction has an average particle size (d50) in the range of 2 to 200 μm, preferably 2 to 100 μm, more preferably 2 to 50 μm, most preferably 2 to 20 μm, and the first and The pigment composition, wherein the second particle fraction is surface-treated.   The pigment composition according to claim 1, wherein the inorganic pigment particles are metal salts.   The pigment composition according to claim 2, wherein the metal salt is a metal oxide.   4. The pigment composition according to claim 3, wherein the metal oxide is titanium dioxide. The pigment particles are surface-treated with a compound of aluminum, silicon, titanium, zirconium, tin, cerium or phosphorus and / or an organic compound selected from the group of silane, siloxane, TMP, TME and HMP. The pigment composition according to any one of claims 1 to 4. The first and second particle fractions are subjected to the same surface treatment; and / or particles of the second particle fraction in which the pigment composition is 1 to 8% by weight, preferably 3 to 6% by weight The pigment composition according to any one of claims 1 to 5, characterized by comprising: A method for producing a pigment composition for matte coating,
(A) preparing a first inorganic pigment particle fraction having a colorable particle size;
(B) preparing a second inorganic pigment particle fraction having an average particle diameter (d50) in the range of 2 to 200 μm, preferably 2 to 100 μm, more preferably 2 to 50 μm, and most preferably 2 to 20 μm. And (c) the production method comprising a step of surface-treating the first and second pigment particle fractions in an aqueous suspension. The method of claim 7, comprising:
The particles of the first and second particle fractions are metal oxides and / or the particles of the first and second particle fractions are metal salts and / or the first and second The method according to claim 7, characterized in that the particles of the two particle fractions are titanium dioxide. The surface treatment is an inorganic and / or organic surface treatment; and / or the particles of the first and second particle fractions are a compound of aluminum, silicon, titanium, zirconium, tin, cerium or phosphorus and / or silane The method according to claim 7, wherein the surface treatment is performed with an organic compound selected from the group consisting of siloxane, TMP, TME, and HMP. Either both the first and second particle fractions are surface treated together; or the first and second particle fractions are surface treated separately, but surface treated in the same manner, Item 10. The method according to any one of Items 7 to 9.   7. Coating formulation for producing a pigmented matte surface, characterized in that it comprises a pigment composition according to any one of claims 1-6.   A matte surface colored with a pigment of a substrate, characterized in that it is coated with the coating formulation according to claim 11.   Matte coating colored with pigments such as paints and printing inks, characterized in that the pigment composition according to any one of claims 1 to 6 is used.   A plastic containing a matting agent, comprising the pigment composition according to any one of claims 1 to 6.   Use of the pigment composition according to any one of claims 1 to 6 for matting a substrate.